Methods for preparing nickel-cobalt-aluminum precursor material and cathode material with gradient distribution of aluminum element

#The present application is the US national phase of PCT application No. PCT/CN2016/081350, which was filed on May 6, 2016 and titled “METHODS FOR PREPARING NICKEL-COBALT-ALUMINUM PRECURSOR MATERIAL AND CATHODE MATERIAL WITH GRADIENT DISTRIBUTION OF ALUMINUM ELEMENT”, which claims priority from Chinese Patent Application No. 201510233112.6, which was filed on May 8, 2015 and titled “METHODS FOR PREPARING NICKEL-COBALT-ALUMINUM PRECURSOR MATERIAL AND CATHODE MATERIAL WITH GRADIENT DISTRIBUTION OF ALUMINUM ELEMENT”, which is incorporated herein by reference in its entirety.

#The present disclosure relates to the field of manufacture of lithium ion batteries, and specifically to methods for preparing a nickel-cobalt-aluminum precursor material and a cathode material with gradient distribution of aluminum element.

#So far, lithium ion batteries have been widely used in the fields of various mobile electronic products and electric tools. The cathode material is a key to improving the energy density and the safety and reducing the cost in lithium ion batteries. Further improving the power density, the energy density and the safety performance of the material is the recent direction of the development in cathode materials for lithium ion batteries.

#By reading the following detailed description of embodiments, various other advantages and benefits will become apparent to a person skilled in the art. The drawings are only used to illustrate embodiments, and should not be considered as limitations to the present disclosure. In the drawings:

#FIG. 1 is a schematic diagram of the mode for feeding various raw materials in the synthetic method of the present disclosure.

#FIG. 2 is a SEM image of the precursor prepared in Example 1.

#Exemplary embodiments of the present disclosure will be described below in more details. Although exemplary embodiments of the present disclosure are shown below, it should be understood that the present disclosure may be implemented in various forms which should not be limited to the embodiments set forth herein. Instead, these embodiments are provided to render a more thorough understanding of the present disclosure, and to convey the scope of the disclosure completely to a person skilled in the art. It should be understood that a person skilled in the art can recognize various methods, components, and contents which, although not explicitly described or disclosed in this specification, realize the present disclosure and are within the spirit, principle and scope of the present disclosure. All examples and conditional language recited in this specification are for purposes of illustration and teaching, so as to help the reader understand the principle and concept of the contributions made by the inventors to the prior art, which should not be construed as being limited to these specifically recited examples and conditions. In addition, for the sake of clarity, detailed descriptions of known methods, components and contents are omitted, so as not to obscure the description of the present disclosure. It should be understood that the features in various embodiments described herein may be combined with each other, unless specifically stated otherwise.

#The following solutions were prepared: 45 L aqueous solution of nickel and cobalt salts with a Ni+Co ion concentration of 2 mol/L and Ni:Co=81.5:15; 30 L solution of sodium hydroxide with a mass concentration of 32%; 20 L aqueous solution of ammonia (the solution containing the complexing agent II) with a concentration of 14 mol/L; 3.26 L solution of sodium metaaluminate (a complexing solution of aluminum and hydroxide) (the aluminum complexing solution) with an aluminum element content of 1 mol/L; and 41.74 L solution of sodium hydroxide (the solution containing the complexing agent I) with a pH value of 12.

#40 L aqueous ammonia was added in advance into a 150 L reaction kettle at a temperature of 50° C. to give an aqueous solution having a (NH3·H2O+NH4+) concentration of 1 mol/L and a pH value of 11.50±0.02. The pH value was measured with a pH meter, and the (NH3·H2O+NH4+) concentration was measure with a chemical titration method and was adjusted by controlling the rate for adding concentrated aqueous ammonia.